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CAUTION!
The required concentration may vary
depending on the type of glycol. ALWAYS
compare the requirements from the table
above with the specifications provided by
the glycol manufacturer. If necessary, meet
the requirements set by the glycol manufac-
turer.
The added concentration of glycol must
NEVER exceed 35%.
If the fluid in the system is frozen, the pump
CANNOT start. Mind that if you only prevent
the system from bursting, the liquid inside
might still freeze.
If NO glycol has been added to the system
and a power failure or a pump failure occurs,
drain the water from the system.
When the water inside the system is
stationary, it can easily freeze and thus
damage the system.
CAUTION!
Use only propylene glycol including the required
inhibitors, classified as category III as per
EN 1717.
CAUTION!
Glycol absorbs water from its environment.
Therefore do NOT add glycol that has been
exposed to air. Leaving the cap off the glycol
container causes the concentration of water to
increase. The glycol concentration is then lower
than assumed. As a result, the hydraulic compo-
nents might freeze up after all. Take preventive
actions to ensure a minimal exposure of the
glycol to air.
FA ROTEX HPSU monobloc compact • 09/2017
7
x
Service and maintenance
CAUTION!
If overpressure occurs, the system releases
some of the fluid through the pressure relief
valve. If glycol was added to the system,
take adequate measures so as to safely
recover it.
Under all circumstances, make sure that the
hose of the pressure relief valve is ALWAYS
free to release the pressure. Prevent water
from staying and/or freezing up inside the
hose.
WARNING!
Due to presence of glycol, corrosion of the
system is possible. Uninhibited glycol will turn
acidic under the influence of oxygen. This pro-
cess is accelerated by the presence of copper
and high temperatures. The acidic uninhibited
glycol attacks metal surfaces and forms gal-
vanic corrosion cells that cause severe damage
to the system. Therefore it is important that:
water treatment is performed by a qualified
water specialist;
glycol with corrosion inhibitors is selected to
counteract acids formed by the oxidation of
glycol;
no automotive glycol must be used, because
its corrosion inhibitors have a limited lifetime
and contain silicates which can contaminate
or clog the system;
galvanized pipes must NOT be used in glycol
systems, as the precipitation of certain
components in the glycol's corrosion inhibitor
may occur.
Adding glycol to the water circuit reduces the maximum allowed
water volume of the system. Further information can be found in
the chapter "Checking the water volume and flow rate" in the ref-
erence manual for the technician.
7.4.2 Filling, topping up steps
1. Connect the filling hose (fig. 7-2, item 1) with the non-return
valve and an external manometer
the KFE cock (fig. 7-2, item 2) and secure it against slipping
off with a hose clamp.
2. Make sure that the automatic vent valve cap is open (fig. 5-3,
item A).
1)
if not already installed in the heating system
1)
(on the building side) to
45
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